Not only does the beat go on; it's the same old beat. I seem to have read -- or at least heard -- most of it before, and what little I haven't (notably, that John F. Kennedy was "wrongly diagnosed and treated for Addison's disease and would likely have died in office" had he been re-elected) appears to have little bearing on the assassination.

Nevertheless, the book is already doing well -- it was sixth on the New York Times best-seller list last Sunday -- and that's not surprising, given the popularity of Oliver Stone's film, "JFK" (which Mr. Livingstone spends an entire chapter panning), books by Jim Garrison and Mark Lane, plus assorted TV documentaries, including a program on "Nova," narrated by Walter Cronkite, which tended to support the Warren Commission conclusions. Finally, there is George Paige's "The JFK Conspiracy," which attempts to link the assassination to Watergate and Richard Nixon.

But what have we here? Essentially, we have a rambling, repetitive, frequently confusing, often intriguing but ultimately mind-numbing rehash of "High Treason" and other assassination literature. It's not that Mr. Livingstone hasn't done his homework. Few have been more single-mindedly obsessed with the assassination of President Kennedy. But he and his fellow theorists have almost exhausted the vein. And they are no closer to proving -- conclusively -- that there was more than one assassin, more than two bullets.

"High Treason 2" begins with a rather mawkish tribute to Kennedy and moves on to a lengthy list of those he offended in his brief time in Camelot and who "got him back." The list includes survivors from the Bay of Pigs fiasco, the military, the intelligence community, assorted political and industrial power brokers and members of the radical right.

Some, the author alleges, were stung by Kennedy's half-hearted support of the Bay of Pigs. Others objected to the 1963 nuclear test ban treaty with the Soviet Union. Still others were "threatened to the core of their lives" by Kennedy's proposal to reduce oil-depletion allowances.

Mr. Livingstone interviews dozens of people involved directly or indirectly in the assassination: photographers, ambulance drivers, funeral directors, Secret Service agents, even the nurse in Dallas who ordered a body bag for the president. He speaks at length with a Navy corpsman who insisted Kennedy's brain "virtually fell out" of his head during the autopsy, and he quotes a doctor who examined the X-rays of Kennedy's skull and found nothing wrong with them, contrary to Mr. Livingstone's compelling claim that they were faked, as were the photographs taken at the autopsy.

There's more. Much more. Mr. Livingstone re-examines the Abraham Zapruder film and pronounces it doctored. He lists other major political killings in the U.S. that followed Kennedy's assassination and draws connections between those deaths and Kennedy's. He uncovers a supposed link between the Kennedy killing and the Watergate break-in. And he proposes that the U.S. Senate investigate the assassination.

Mr. Livingstone is certainly correct when he says that the way things stand now, unless one of the participants in the alleged conspiracy talks or leaves some sort of documentation in our lifetime, we'll probably never know much more than we know today.